Dried Porous Biomaterials from Mealworm Protein Gels: Proof of Concept and Impact of Drying Method on Structural Properties and Zinc Retention.

Dried porous materials can be found in a wide range of applications. So far, they are mostly prepared from inorganic or indigestible raw materials. The aim of the presented study was to provide a proof of concept for (a) the suitability of mealworm protein gels to be turned into dried porous biomaterials by either a combination of solvent exchange and supercritical drying to obtain aerogels or by lyophilization to obtain lyophilized hydrogels and (b) the suitability of either drying method to retain trace elements such as zinc in the gels throughout the drying process. Hydrogels were prepared from mealworm protein, subsequently dried using either method, and characterized via FT-IR, BET volume, and high-resolution scanning electron microscopy. Retention of zinc was evaluated via energy-dispersive X-ray spectroscopy. Results showed that both drying methods were suitable for obtaining dried porous biomaterials and that the drying method mainly influenced the overall surface area and pore hydrophobicity but not the secondary structure of the proteins in the gels or their zinc content after drying. Therefore, a first proof of concept for utilizing mealworm protein hydrogels as a base for dried porous biomaterials was successful and elucidated the potential of these materials as future sustainable alternatives to more conventional dried porous materials.

A Novel Collagen Aerogel with Relevant Features for Topical Biomedical Applications.

Collagen-based aerogels have great potential for topical biomedical applications. Collagen's natural affinity with skin, biodegradability, and gelling behavior are compelling properties to combine with the structural integrity of highly porous matrices in the dry form (aerogels). This work aimed to produce a novel collagen-based aerogel and to perform the material's solid-state and physicochemical characterization. Aerogels were obtained by performing different solvent exchange approaches of a collagen-gelled extract and drying the obtained alcogels with supercritical CO2. The resulting aerogels showed a sponge-like structure with a relatively dense mesoporous network with a specific surface area of 201-203 m2/g, a specific pore volume of 1.08-1.15 cm3/g, and a mean pore radius of ca. 14.7 nm. Physicochemical characterization confirmed that the obtained aerogels are composed of pure collagen, and the aerogel production process does not impact protein tertiary structure. Finally, the material swelling behavior was assessed at various pH values (4, 7, and 10). Collagen aerogels presented a high water uptake capacity up to ~2700 wt. %, pH-dependent stability, and swelling behavior in aqueous media. The results suggest that this collagen aerogel could be a promising scaffold candidate for topical biomedical applications.